Re: [PATCH] udf: use crc_itu_t from lib instead of udf_crc

From: Jan Kara
Date: Thu Apr 17 2008 - 03:52:10 EST

Hello,

On Wed 16-04-08 21:07:11, Bob Copeland wrote:
> In reviewing a patch of mine, Sergey Vlasov noticed that the CRC used
> in UDF was recently added to lib/. Would you accept a patch to switch
> UDF over? Such as:
Thanks for the patch. It is fine, only I had to do some merging because
of other cleanups clashing with your patch. Could you please generate the
diff against -mm kernel or UDF git
(git.kernel.org//pub/scm/linux/kernel/git/jack/linux-udf-2.6.git for_mm)
next time? It would be easier for me. Thanks.

Honza

> From: Bob Copeland <me@xxxxxxxxxxxxxxx>
> Date: Wed, 16 Apr 2008 20:23:31 -0400
> Subject: [PATCH] udf: use crc_itu_t from lib instead of udf_crc
>
> As pointed out by Sergey Vlasov, UDF implements its own version of
> the CRC ITU-T V.41. Convert it to use the one in the library.
>
> Signed-off-by: Bob Copeland <me@xxxxxxxxxxxxxxx>
> Cc: Sergey Vlasov <vsu@xxxxxxxxxxx>
> ---
> fs/Kconfig | 1 +
> fs/udf/Makefile | 2 +-
> fs/udf/crc.c | 172 ------------------------------------------------------
> fs/udf/inode.c | 11 ++--
> fs/udf/misc.c | 12 ++--
> fs/udf/namei.c | 21 +++----
> fs/udf/super.c | 11 ++--
> fs/udf/udfdecl.h | 3 -
> fs/udf/unicode.c | 3 +-
> 9 files changed, 32 insertions(+), 204 deletions(-)
> delete mode 100644 fs/udf/crc.c
>
> diff --git a/fs/Kconfig b/fs/Kconfig
> index 5dd8f94..f18564f 100644
> --- a/fs/Kconfig
> +++ b/fs/Kconfig
> @@ -663,6 +663,7 @@ config ZISOFS
>
> config UDF_FS
> tristate "UDF file system support"
> + select CRC_ITU_T
> help
> This is the new file system used on some CD-ROMs and DVDs. Say Y if
> you intend to mount DVD discs or CDRW's written in packet mode, or
> diff --git a/fs/udf/Makefile b/fs/udf/Makefile
> index be845e7..0d4503f 100644
> --- a/fs/udf/Makefile
> +++ b/fs/udf/Makefile
> @@ -6,4 +6,4 @@ obj-$(CONFIG_UDF_FS) += udf.o
>
> udf-objs := balloc.o dir.o file.o ialloc.o inode.o lowlevel.o namei.o \
> partition.o super.o truncate.o symlink.o fsync.o \
> - crc.o directory.o misc.o udftime.o unicode.o
> + directory.o misc.o udftime.o unicode.o
> diff --git a/fs/udf/crc.c b/fs/udf/crc.c
> deleted file mode 100644
> index b166129..0000000
> --- a/fs/udf/crc.c
> +++ /dev/null
> @@ -1,172 +0,0 @@
> -/*
> - * crc.c
> - *
> - * PURPOSE
> - * Routines to generate, calculate, and test a 16-bit CRC.
> - *
> - * DESCRIPTION
> - * The CRC code was devised by Don P. Mitchell of AT&T Bell Laboratories
> - * and Ned W. Rhodes of Software Systems Group. It has been published in
> - * "Design and Validation of Computer Protocols", Prentice Hall,
> - * Englewood Cliffs, NJ, 1991, Chapter 3, ISBN 0-13-539925-4.
> - *
> - * Copyright is held by AT&T.
> - *
> - * AT&T gives permission for the free use of the CRC source code.
> - *
> - * COPYRIGHT
> - * This file is distributed under the terms of the GNU General Public
> - * License (GPL). Copies of the GPL can be obtained from:
> - * ftp://prep.ai.mit.edu/pub/gnu/GPL
> - * Each contributing author retains all rights to their own work.
> - */
> -
> -#include "udfdecl.h"
> -
> -static uint16_t crc_table[256] = {
> - 0x0000U, 0x1021U, 0x2042U, 0x3063U, 0x4084U, 0x50a5U, 0x60c6U, 0x70e7U,
> - 0x8108U, 0x9129U, 0xa14aU, 0xb16bU, 0xc18cU, 0xd1adU, 0xe1ceU, 0xf1efU,
> - 0x1231U, 0x0210U, 0x3273U, 0x2252U, 0x52b5U, 0x4294U, 0x72f7U, 0x62d6U,
> - 0x9339U, 0x8318U, 0xb37bU, 0xa35aU, 0xd3bdU, 0xc39cU, 0xf3ffU, 0xe3deU,
> - 0x2462U, 0x3443U, 0x0420U, 0x1401U, 0x64e6U, 0x74c7U, 0x44a4U, 0x5485U,
> - 0xa56aU, 0xb54bU, 0x8528U, 0x9509U, 0xe5eeU, 0xf5cfU, 0xc5acU, 0xd58dU,
> - 0x3653U, 0x2672U, 0x1611U, 0x0630U, 0x76d7U, 0x66f6U, 0x5695U, 0x46b4U,
> - 0xb75bU, 0xa77aU, 0x9719U, 0x8738U, 0xf7dfU, 0xe7feU, 0xd79dU, 0xc7bcU,
> - 0x48c4U, 0x58e5U, 0x6886U, 0x78a7U, 0x0840U, 0x1861U, 0x2802U, 0x3823U,
> - 0xc9ccU, 0xd9edU, 0xe98eU, 0xf9afU, 0x8948U, 0x9969U, 0xa90aU, 0xb92bU,
> - 0x5af5U, 0x4ad4U, 0x7ab7U, 0x6a96U, 0x1a71U, 0x0a50U, 0x3a33U, 0x2a12U,
> - 0xdbfdU, 0xcbdcU, 0xfbbfU, 0xeb9eU, 0x9b79U, 0x8b58U, 0xbb3bU, 0xab1aU,
> - 0x6ca6U, 0x7c87U, 0x4ce4U, 0x5cc5U, 0x2c22U, 0x3c03U, 0x0c60U, 0x1c41U,
> - 0xedaeU, 0xfd8fU, 0xcdecU, 0xddcdU, 0xad2aU, 0xbd0bU, 0x8d68U, 0x9d49U,
> - 0x7e97U, 0x6eb6U, 0x5ed5U, 0x4ef4U, 0x3e13U, 0x2e32U, 0x1e51U, 0x0e70U,
> - 0xff9fU, 0xefbeU, 0xdfddU, 0xcffcU, 0xbf1bU, 0xaf3aU, 0x9f59U, 0x8f78U,
> - 0x9188U, 0x81a9U, 0xb1caU, 0xa1ebU, 0xd10cU, 0xc12dU, 0xf14eU, 0xe16fU,
> - 0x1080U, 0x00a1U, 0x30c2U, 0x20e3U, 0x5004U, 0x4025U, 0x7046U, 0x6067U,
> - 0x83b9U, 0x9398U, 0xa3fbU, 0xb3daU, 0xc33dU, 0xd31cU, 0xe37fU, 0xf35eU,
> - 0x02b1U, 0x1290U, 0x22f3U, 0x32d2U, 0x4235U, 0x5214U, 0x6277U, 0x7256U,
> - 0xb5eaU, 0xa5cbU, 0x95a8U, 0x8589U, 0xf56eU, 0xe54fU, 0xd52cU, 0xc50dU,
> - 0x34e2U, 0x24c3U, 0x14a0U, 0x0481U, 0x7466U, 0x6447U, 0x5424U, 0x4405U,
> - 0xa7dbU, 0xb7faU, 0x8799U, 0x97b8U, 0xe75fU, 0xf77eU, 0xc71dU, 0xd73cU,
> - 0x26d3U, 0x36f2U, 0x0691U, 0x16b0U, 0x6657U, 0x7676U, 0x4615U, 0x5634U,
> - 0xd94cU, 0xc96dU, 0xf90eU, 0xe92fU, 0x99c8U, 0x89e9U, 0xb98aU, 0xa9abU,
> - 0x5844U, 0x4865U, 0x7806U, 0x6827U, 0x18c0U, 0x08e1U, 0x3882U, 0x28a3U,
> - 0xcb7dU, 0xdb5cU, 0xeb3fU, 0xfb1eU, 0x8bf9U, 0x9bd8U, 0xabbbU, 0xbb9aU,
> - 0x4a75U, 0x5a54U, 0x6a37U, 0x7a16U, 0x0af1U, 0x1ad0U, 0x2ab3U, 0x3a92U,
> - 0xfd2eU, 0xed0fU, 0xdd6cU, 0xcd4dU, 0xbdaaU, 0xad8bU, 0x9de8U, 0x8dc9U,
> - 0x7c26U, 0x6c07U, 0x5c64U, 0x4c45U, 0x3ca2U, 0x2c83U, 0x1ce0U, 0x0cc1U,
> - 0xef1fU, 0xff3eU, 0xcf5dU, 0xdf7cU, 0xaf9bU, 0xbfbaU, 0x8fd9U, 0x9ff8U,
> - 0x6e17U, 0x7e36U, 0x4e55U, 0x5e74U, 0x2e93U, 0x3eb2U, 0x0ed1U, 0x1ef0U
> -};
> -
> -/*
> - * udf_crc
> - *
> - * PURPOSE
> - * Calculate a 16-bit CRC checksum using ITU-T V.41 polynomial.
> - *
> - * DESCRIPTION
> - * The OSTA-UDF(tm) 1.50 standard states that using CRCs is mandatory.
> - * The polynomial used is: x^16 + x^12 + x^15 + 1
> - *
> - * PRE-CONDITIONS
> - * data Pointer to the data block.
> - * size Size of the data block.
> - *
> - * POST-CONDITIONS
> - * <return> CRC of the data block.
> - *
> - * HISTORY
> - * July 21, 1997 - Andrew E. Mileski
> - * Adapted from OSTA-UDF(tm) 1.50 standard.
> - */
> -uint16_t udf_crc(uint8_t *data, uint32_t size, uint16_t crc)
> -{
> - while (size--)
> - crc = crc_table[(crc >> 8 ^ *(data++)) & 0xffU] ^ (crc << 8);
> -
> - return crc;
> -}
> -
> -/****************************************************************************/
> -#if defined(TEST)
> -
> -/*
> - * PURPOSE
> - * Test udf_crc()
> - *
> - * HISTORY
> - * July 21, 1997 - Andrew E. Mileski
> - * Adapted from OSTA-UDF(tm) 1.50 standard.
> - */
> -
> -unsigned char bytes[] = { 0x70U, 0x6AU, 0x77U };
> -
> -int main(void)
> -{
> - unsigned short x;
> -
> - x = udf_crc(bytes, sizeof bytes);
> - printf("udf_crc: calculated = %4.4x, correct = %4.4x\n", x, 0x3299U);
> -
> - return 0;
> -}
> -
> -#endif /* defined(TEST) */
> -
> -/****************************************************************************/
> -#if defined(GENERATE)
> -
> -/*
> - * PURPOSE
> - * Generate a table for fast 16-bit CRC calculations (any polynomial).
> - *
> - * DESCRIPTION
> - * The ITU-T V.41 polynomial is 010041.
> - *
> - * HISTORY
> - * July 21, 1997 - Andrew E. Mileski
> - * Adapted from OSTA-UDF(tm) 1.50 standard.
> - */
> -
> -#include <stdio.h>
> -
> -int main(int argc, char **argv)
> -{
> - unsigned long crc, poly;
> - int n, i;
> -
> - /* Get the polynomial */
> - sscanf(argv[1], "%lo", &poly);
> - if (poly & 0xffff0000U) {
> - fprintf(stderr, "polynomial is too large\en");
> - exit(1);
> - }
> -
> - printf("/* CRC 0%o */\n", poly);
> -
> - /* Create a table */
> - printf("static unsigned short crc_table[256] = {\n");
> - for (n = 0; n < 256; n++) {
> - if (n % 8 == 0)
> - printf("\t");
> - crc = n << 8;
> - for (i = 0; i < 8; i++) {
> - if (crc & 0x8000U)
> - crc = (crc << 1) ^ poly;
> - else
> - crc <<= 1;
> - crc &= 0xFFFFU;
> - }
> - if (n == 255)
> - printf("0x%04xU ", crc);
> - else
> - printf("0x%04xU, ", crc);
> - if (n % 8 == 7)
> - printf("\n");
> - }
> - printf("};\n");
> -
> - return 0;
> -}
> -
> -#endif /* defined(GENERATE) */
> diff --git a/fs/udf/inode.c b/fs/udf/inode.c
> index 24cfa55..97297e7 100644
> --- a/fs/udf/inode.c
> +++ b/fs/udf/inode.c
> @@ -37,6 +37,7 @@
> #include <linux/buffer_head.h>
> #include <linux/writeback.h>
> #include <linux/slab.h>
> +#include <linux/crc-itu-t.h>
>
> #include "udf_i.h"
> #include "udf_sb.h"
> @@ -1488,9 +1489,9 @@ static int udf_update_inode(struct inode *inode, int do_sync)
> iinfo->i_location.
> logicalBlockNum);
> use->descTag.descCRCLength = cpu_to_le16(crclen);
> - use->descTag.descCRC = cpu_to_le16(udf_crc((char *)use +
> - sizeof(tag), crclen,
> - 0));
> + use->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)use +
> + sizeof(tag),
> + crclen));
> use->descTag.tagChecksum = udf_tag_checksum(&use->descTag);
>
> mark_buffer_dirty(bh);
> @@ -1660,8 +1661,8 @@ static int udf_update_inode(struct inode *inode, int do_sync)
> crclen += iinfo->i_lenEAttr + iinfo->i_lenAlloc -
> sizeof(tag);
> fe->descTag.descCRCLength = cpu_to_le16(crclen);
> - fe->descTag.descCRC = cpu_to_le16(udf_crc((char *)fe + sizeof(tag),
> - crclen, 0));
> + fe->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)fe + sizeof(tag),
> + crclen));
> fe->descTag.tagChecksum = udf_tag_checksum(&fe->descTag);
>
> /* write the data blocks */
> diff --git a/fs/udf/misc.c b/fs/udf/misc.c
> index a1d6da0..532bdf0 100644
> --- a/fs/udf/misc.c
> +++ b/fs/udf/misc.c
> @@ -25,6 +25,7 @@
> #include <linux/string.h>
> #include <linux/udf_fs.h>
> #include <linux/buffer_head.h>
> +#include <linux/crc-itu-t.h>
>
> #include "udf_i.h"
> #include "udf_sb.h"
> @@ -136,8 +137,8 @@ struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,
> /* rewrite CRC + checksum of eahd */
> crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(tag);
> eahd->descTag.descCRCLength = cpu_to_le16(crclen);
> - eahd->descTag.descCRC = cpu_to_le16(udf_crc((char *)eahd +
> - sizeof(tag), crclen, 0));
> + eahd->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)eahd +
> + sizeof(tag), crclen));
> eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag);
> iinfo->i_lenEAttr += size;
> return (struct genericFormat *)&ea[offset];
> @@ -244,8 +245,9 @@ struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,
>
> /* Verify the descriptor CRC */
> if (le16_to_cpu(tag_p->descCRCLength) + sizeof(tag) > sb->s_blocksize ||
> - le16_to_cpu(tag_p->descCRC) == udf_crc(bh->b_data + sizeof(tag),
> - le16_to_cpu(tag_p->descCRCLength), 0))
> + le16_to_cpu(tag_p->descCRC) == crc_itu_t(0,
> + bh->b_data + sizeof(tag),
> + le16_to_cpu(tag_p->descCRCLength)))
> return bh;
>
> udf_debug("Crc failure block %d: crc = %d, crclen = %d\n",
> @@ -270,7 +272,7 @@ void udf_update_tag(char *data, int length)
> length -= sizeof(tag);
>
> tptr->descCRCLength = cpu_to_le16(length);
> - tptr->descCRC = cpu_to_le16(udf_crc(data + sizeof(tag), length, 0));
> + tptr->descCRC = cpu_to_le16(crc_itu_t(0, data + sizeof(tag), length));
> tptr->tagChecksum = udf_tag_checksum(tptr);
> }
>
> diff --git a/fs/udf/namei.c b/fs/udf/namei.c
> index 112a5fb..168d2e9 100644
> --- a/fs/udf/namei.c
> +++ b/fs/udf/namei.c
> @@ -31,6 +31,7 @@
> #include <linux/smp_lock.h>
> #include <linux/buffer_head.h>
> #include <linux/sched.h>
> +#include <linux/crc-itu-t.h>
>
> static inline int udf_match(int len1, const char *name1, int len2,
> const char *name2)
> @@ -97,25 +98,23 @@ int udf_write_fi(struct inode *inode, struct fileIdentDesc *cfi,
> memset(fibh->ebh->b_data, 0x00, padlen + offset);
> }
>
> - crc = udf_crc((uint8_t *)cfi + sizeof(tag),
> - sizeof(struct fileIdentDesc) - sizeof(tag), 0);
> + crc = crc_itu_t(0, (uint8_t *)cfi + sizeof(tag),
> + sizeof(struct fileIdentDesc) - sizeof(tag));
>
> if (fibh->sbh == fibh->ebh) {
> - crc = udf_crc((uint8_t *)sfi->impUse,
> + crc = crc_itu_t(crc, (uint8_t *)sfi->impUse,
> crclen + sizeof(tag) -
> - sizeof(struct fileIdentDesc), crc);
> + sizeof(struct fileIdentDesc));
> } else if (sizeof(struct fileIdentDesc) >= -fibh->soffset) {
> - crc = udf_crc(fibh->ebh->b_data +
> + crc = crc_itu_t(crc, fibh->ebh->b_data +
> sizeof(struct fileIdentDesc) +
> fibh->soffset,
> crclen + sizeof(tag) -
> - sizeof(struct fileIdentDesc),
> - crc);
> + sizeof(struct fileIdentDesc));
> } else {
> - crc = udf_crc((uint8_t *)sfi->impUse,
> - -fibh->soffset - sizeof(struct fileIdentDesc),
> - crc);
> - crc = udf_crc(fibh->ebh->b_data, fibh->eoffset, crc);
> + crc = crc_itu_t(crc, (uint8_t *)sfi->impUse,
> + -fibh->soffset - sizeof(struct fileIdentDesc));
> + crc = crc_itu_t(crc, fibh->ebh->b_data, fibh->eoffset);
> }
>
> cfi->descTag.descCRC = cpu_to_le16(crc);
> diff --git a/fs/udf/super.c b/fs/udf/super.c
> index f3ac4ab..a8194c7 100644
> --- a/fs/udf/super.c
> +++ b/fs/udf/super.c
> @@ -55,6 +55,7 @@
> #include <linux/errno.h>
> #include <linux/mount.h>
> #include <linux/seq_file.h>
> +#include <linux/crc-itu-t.h>
> #include <asm/byteorder.h>
>
> #include <linux/udf_fs.h>
> @@ -1644,9 +1645,8 @@ static void udf_open_lvid(struct super_block *sb)
> lvid->integrityType = LVID_INTEGRITY_TYPE_OPEN;
>
> lvid->descTag.descCRC = cpu_to_le16(
> - udf_crc((char *)lvid + sizeof(tag),
> - le16_to_cpu(lvid->descTag.descCRCLength),
> - 0));
> + crc_itu_t(0, (char *)lvid + sizeof(tag),
> + le16_to_cpu(lvid->descTag.descCRCLength)));
>
> lvid->descTag.tagChecksum = udf_tag_checksum(&lvid->descTag);
> mark_buffer_dirty(bh);
> @@ -1682,9 +1682,8 @@ static void udf_close_lvid(struct super_block *sb)
> lvid->integrityType = cpu_to_le32(LVID_INTEGRITY_TYPE_CLOSE);
>
> lvid->descTag.descCRC = cpu_to_le16(
> - udf_crc((char *)lvid + sizeof(tag),
> - le16_to_cpu(lvid->descTag.descCRCLength),
> - 0));
> + crc_itu_t(0, (char *)lvid + sizeof(tag),
> + le16_to_cpu(lvid->descTag.descCRCLength)));
>
> lvid->descTag.tagChecksum = udf_tag_checksum(&lvid->descTag);
> mark_buffer_dirty(bh);
> diff --git a/fs/udf/udfdecl.h b/fs/udf/udfdecl.h
> index 681dc2b..82ac3aa 100644
> --- a/fs/udf/udfdecl.h
> +++ b/fs/udf/udfdecl.h
> @@ -191,9 +191,6 @@ extern struct fileIdentDesc *udf_get_fileident(void *buffer, int bufsize,
> extern long_ad *udf_get_filelongad(uint8_t *, int, uint32_t *, int);
> extern short_ad *udf_get_fileshortad(uint8_t *, int, uint32_t *, int);
>
> -/* crc.c */
> -extern uint16_t udf_crc(uint8_t *, uint32_t, uint16_t);
> -
> /* udftime.c */
> extern time_t *udf_stamp_to_time(time_t *, long *, kernel_timestamp);
> extern kernel_timestamp *udf_time_to_stamp(kernel_timestamp *, struct timespec);
> diff --git a/fs/udf/unicode.c b/fs/udf/unicode.c
> index e533b11..e951cca 100644
> --- a/fs/udf/unicode.c
> +++ b/fs/udf/unicode.c
> @@ -24,6 +24,7 @@
> #include <linux/string.h> /* for memset */
> #include <linux/nls.h>
> #include <linux/udf_fs.h>
> +#include <linux/crc-itu-t.h>
>
> #include "udf_sb.h"
>
> @@ -463,7 +464,7 @@ static int udf_translate_to_linux(uint8_t *newName, uint8_t *udfName,
> } else if (newIndex > 250)
> newIndex = 250;
> newName[newIndex++] = CRC_MARK;
> - valueCRC = udf_crc(fidName, fidNameLen, 0);
> + valueCRC = crc_itu_t(0, fidName, fidNameLen);
> newName[newIndex++] = hexChar[(valueCRC & 0xf000) >> 12];
> newName[newIndex++] = hexChar[(valueCRC & 0x0f00) >> 8];
> newName[newIndex++] = hexChar[(valueCRC & 0x00f0) >> 4];
> --
> 1.5.4.2.182.gb3092
>
> --
> Bob Copeland %% www.bobcopeland.com
>
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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